title: Screening and identification of a novel esterase EstPE from a metagenomic DNA library.
abstract: Esterases represent a large family of hydrolases with broad substrate specificity and functional sequence space. Although many attempts to screen new esterases have been conducted, there have been few reports conducted to discriminate unique enzymes from typical ones based on novel structure and function. In this study, we discovered an esterase and a novel family through a successive assay of whole cells and crude lysates (oxidative open condition). The screened putative esterases from the metagenomic DNA of salted shrimp consisted of 753 bp encoding 27 kDa of polypeptide, namely PE esterase. Sequence analyses revealed that an identical gene was reported from whole genome sequencing of Stenotrophomonas maltophilia K279a. However, its biochemical and phylogenetic characteristics have not yet been evaluated. PE esterase was overexpressed only by the MBP fusion state in E. coli and was easily purified using an affinity column. This enzyme showed a typical spectrum of substrate specificity and possessed the consensus motifs, Ser-Asp-His and GXSXG, which are essential for most esterase/lipase superfamilies. Interestingly, the entire organization of the ORF and consensus sequence around the active site were distinct from the related enzymes, and its structure could be affected by a reducing agent, DTT.
authors.affiliation: Department of Biological Sciences, College of Natural Sciences, Chonnam National University, Gwangju, 500-757, Republic of Korea.
authors.forename: So-Youn
authors.initials: SY
authors.lastname: Park
authors.forename: Hyun-Jae
authors.initials: HJ
authors.lastname: Shin
authors.forename: Geun-Joong
authors.initials: GJ
authors.lastname: Kim
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics; D004950:Esterases / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D005516:Food Microbiology; D015870:Gene Expression; D015723:Gene Library; D054892:Metagenome; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010802:Phylogeny; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D020615:Stenotrophomonas maltophilia / Q000201:enzymology / Q000235:genetics
chemical_list: D011994:Recombinant Proteins; D004950:Esterases